In this particular case, it is a member who is definitely very irritating with his constant repetition of questions, but in the worst case he deserves only neutral feedback. I’ve seen some other DT members do the same thing and most members turn their heads away from it as if it’s a normal occurrence.
I think spamming and trust system are two entirely different, if the post of the member is considered spam, the best is to report to moderators, even it does not deserve either neutral or negative trust. Like you implied, trust system are for people you you trust which you can award +ve, while the negative should be people that are likely moving towards scamming people. Someone can be tagged neutral if you think he can be trusted, although there are many other reasons someone can be tagged neutral in which he is not that trusted but not deserving -ve trusted, such person can be tagged neutral also. In these cases, jerry0 has done nothing that deserves him the negative trust, neither did he do anything that deserves him a neutral trust, all to do regarding spamming is to report to moderators, it is moderators that will consider if the account should be temporary banned, permanently banned, or got some posts deleted.